CN102438250B - Method for employing cooperation analog network coding technology to inhibit inter-cell interference - Google Patents

Abstract

The invention provides a method for employing cooperation analog network coding technology to inhibit inter-cell interference. The method comprises the following steps: two adjacent cooperation cell base stations carry out pairing on edge users, paired users utilize same wireless resource to send information to respective service base station simultaneously, the two cooperation cell base stations receive mixing analog network coding information sent by two users respectively, through cooperation, analog network coding information received by another base station is obtained, and combined detection is carried out on the analog network coding information obtained through cooperation and the received analog network coding information to obtain a sending information of a present cell user. According to the method, under the premise of not changing present communication equipment, inter-cell interference is eliminated, simultaneously since the paired users utilize the same wireless resource to carry out transmission, a defect of a traditional inter-cell interference coordination method is solved, and throughput and frequency spectrum efficiency of the cell edge users are raised.

Description

Adopt cooperation analog network coding technology to suppress the method for presence of intercell interference

Technical field

The present invention relates to a kind of method that adopts cooperation analog network coding technology to suppress presence of intercell interference, belong to the technical field of wireless mobile communications transmission.

Background technology

In order to support more mobile phone users and emerging radio multimedium business, broadband cellular mobile communication system of future generation must reach higher throughput of system and spectrum efficiency.Yet the interference between neighbor cell has made community marginal user performance become the bottleneck of the whole mobile cellular communication systematic function of restriction.

At present, at LTE(Long Term Evolution) etc. in B3G system, mainly adopt Inter-Cell Interference Coordination ICIC(Inter-Cell Interference Coordination) method suppress each presence of intercell interference.The method is to carry out the mutual of relevant information by minizone, makes each community to distribute and for example, to transmit from the resource (adopting different frequency bands) of other neighbor cell quadratures as far as possible for its Cell Edge User, thereby avoids presence of intercell interference.But, in next generation mobile communication, adopt the method for Inter-Cell Interference Coordination, will cause Cell Edge User cannot utilize whole bandwidth of system, this just suppresses the lifting of Wireless Broadband Communication Systems throughput greatly.In addition, LTE system is also supported the presence of intercell interference processing methods such as interference randomization and interference elimination, and interference randomization is by methods such as Direct-Spreads, to alleviate the impact of presence of intercell interference, but it cannot eliminate interference completely.Although disturb to eliminate, can utilize the technology such as wave beam forming to eliminate presence of intercell interference completely,, it for example, to the configuration requirement of system equipment very high (base station and mobile subscriber terminal need configure many antennas).

Network coding technique, by carrying out additional encoding operation at network routing node, can reach the maximum size of single information source network in theory.As the technology of a kind of remarkable raising radio transmission spectrum efficiency and throughput, Wireless Network Coding has caused the extensive concern of industry, by 4G systems such as LTE-Advanced and IEEE802.16m, as alternative technique, is write standard.Current current research result proves, at multiple source, disturbs Adoption Network coding techniques in network also can reach the heap(ed) capacity of Internet Transmission.Wherein, analog network coding is as a kind of important implementation of network code, in research and reality by industry extensive use.Summary of the invention

In view of this, the object of this invention is to provide a kind of method that adopts cooperation analog network coding technology to suppress presence of intercell interference, for solving the problem of inter-cell interference of cell mobile communication systems, improve Cell Edge User with keeping pouring in defeated throughput and spectrum efficiency.

In order to reach foregoing invention object, the invention provides a kind of method that adopts cooperation analog network coding technology to suppress presence of intercell interference, it is characterized in that: match to the user of its cell edge base station, two adjacent cooperation cell, so that primary user and pairing user utilize same wireless resource to send information to serving BS separately simultaneously; Base station, two cooperation cell receives respectively after the analog network coding information sending from two users, by cooperation, obtain the analog network coding information that another base station receives, and the analog network coding information of the analog network coding information that cooperation is obtained and self reception is carried out joint-detection, obtain this community primary user's transmission information, and eliminate the interference from pairing user; The method is not changing under the prerequisite of existing communication equipment, eliminate presence of intercell interference, because pairing user adopts and primary user's same wireless resource is transmitted, solve the deficiency of disturbance coordination method between conventional cell simultaneously, improved throughput and the spectrum efficiency of Cell Edge User; Described method comprises following operating procedure:

(1) two cooperative base station determines that cell edge adopts the excited users pair set of analog network coding transmission, described activation to user by be positioned at the primary user of serving BS and be positioned at cooperative base station, formed with the pairing user of this primary user's pairing; Judge again in this excited users pair set whether have the user couple who needs scheduling, if existed, carry out subsequent step (2); Otherwise, finish this operating process; This step comprises following content of operation:

(11) first cell base station BS1, by measuring the Signal to Interference plus Noise Ratio SINR of user reference signal, judges that whether this community primary user UE1 is this Cell Edge User, if so, carries out subsequent step (12); Otherwise, finish this flow operations;

(12) second cell base station BS2 travel through to find whether have the pairing user who adopts same wireless resource transmission with primary user UE1 in its Cell Edge User, if existed, the user UE2 and the primary user UE1 that meet this condition are matched, the user who again this primary user and pairing user is formed is to putting excited users pair set under, to carry out analog network coding transmission; Otherwise, finishing this flow operations, primary user UE1 adopts traditional non-collaborative network coded system transmission information;

(13) if in excited users pair set, have a plurality of can carry out the candidate user of analog network coding transmission with primary user UE1 pairing time, second base station BS 2 selected a pairing user UE2 from these candidate user according to following formula, allow its analog network coding that cooperates with primary user UE1 pairing transmit, this selection criterion is: , wherein, Σ is the set that all schedulable candidate user form, ue _ifor i user in this set Σ, h ₁, h ₂be respectively the channel fading information of two cooperative base station BS1 of primary user UE1 arrival and BS2, be respectively candidate user ue _iarrive the channel fading information of base station BS 1 and BS2;

(2) dispatch the primary user UE1 of the excited users centering of employing analog network coding transmission and pairing user UE2 according to predetermined priority respectively each base station;

(3) these two user UE1 and UE2 adopt identical Radio Resource to its base station, affiliated subdistrict and base station, adjacent cooperation cell, to send information simultaneously;

(4) two cooperative base station receive respectively the analog network coding information of these two user UE1 and UE2 transmission, also by cooperation, obtain respectively analog network coding information and the required information of detection that another base station receives;

(5) the analog network coding information that each base station obtains cooperation and the analog network coding information self receiving are carried out joint-detection, and the primary user who obtains this community sends information; This step comprises following content of operation:

(51A) base station BS 1 obtains by cooperation the analog network coding information y that another base station BS 2 receives ₂, and primary user UE1 and the channel fading information h of user UE2 to base station BS 2 that match ₁₂and h ₂₂after, the analog network coding information y that base station BS 1 receives self ₁analog network coding information y with cooperation acquisition ₂carry out joint-detection;

(51B) base station BS 2 obtains by cooperation the analog network coding information y that base station BS 1 receives ₁, and primary user UE1 and the channel fading information h of user UE2 to base station BS 1 that match ₁₁and h ₂₁after, the analog network coding information y that base station BS 2 receives self ₂analog network coding information y with cooperation acquisition ₁carry out joint-detection; The operation of this step (51B) is carried out with (51A) simultaneously;

(52) two base station BSs 1 and BS2 adopt respectively following ZF formula to detect to obtain primary user and pairing user's transmission information: ${\left[\begin{array}{cc}{\stackrel{\⩓}{s}}_1& {\stackrel{\⩓}{s}}_2\end{array}\right]}^T=\arg \underset{S_{1-K},S_{2-M}\∈\mathrm{\Ω}}{\min }\left|{\left[\begin{array}{cc}{h}_{11}& h_{12}\\ h_{21}& h_{22}\end{array}\right]}^{-1}{\left[\begin{array}{cc}{y}_1& y_2\end{array}\right]}^T\begin{array}{c}-{\left[\begin{array}{cc}{s}_{1-k}& s_{2-m}\end{array}\right]}^T\end{array}\right|,$ In formula, with respectively that base station BS 1 or BS2 detect two user UE1 obtaining and the transmission information of UE2, Ω be user UE1 and UE2 employing modulation coding mode the likely set of constellation point, s _1-kand s _2-mbe respectively a constellation point in Ω.

The present invention adopts cooperation analog network coding technology to suppress the method for presence of intercell interference, that the communication link situation to this cell base station and neighbor cell base station is more or less the same because of Cell Edge User, therefore can adopt the mode of minizone cooperation, user to two edges, cooperation cell matches, pairing user utilizes same wireless resource to send information simultaneously, two cell base stations receive respectively from two analog subscribers and send after the analog network coding information of information, by cooperation, obtain the analog network coding information that the other side base station receives again, and the analog network coding information of the analog network coding information that cooperation is obtained and self reception is carried out joint-detection, obtain community, place primary user's transmission information.Its advantage: not changing under the prerequisite of existing equipment configuration, just can eliminate presence of intercell interference, the user that simultaneously matches adopts same frequency band to transmit, and has avoided the deficiency of disturbance coordination method between conventional cell, has improved throughput and the spectrum efficiency of community.And the method is simple to operate, it is convenient to realize, and has good popularizing application prospect.

Accompanying drawing explanation

Fig. 1 (A), (B) are respectively that two kinds of network architectures of the inter-cell interference restraint method of collaborative network coding of the present invention form schematic diagram;

Fig. 2 is the inter-cell interference restraint method operating procedure flow chart of collaborative network coding of the present invention

Fig. 3 is that the Cell Edge User throughput ratio of the inventive method and other presence of intercell interference processing methods is compared with schematic diagram;

Embodiment

For making the object, technical solutions and advantages of the present invention clearer, below in conjunction with drawings and Examples, the present invention is described in further detail.

Referring to Fig. 1 (a), introduce the network system architecture figure of method that the present invention adopts the inhibition presence of intercell interference of cooperation analog network coding technology.The inventive method is applicable to two neighbor cell edge customers and carries out uplink, and this two neighbor cell base station X2 interface is interconnected and cooperated by optical fiber.In addition, the inventive method is also applicable to the network system architecture shown in Fig. 1 (b), and the website 1 and 2 in this figure is spaced antennas of relay station or base station, and they are that mode by optical fiber or wireless backhaul link is connected with base station.

The inter-cell interference restraint method of collaborative network coding of the present invention is: match to its Cell Edge User base station, two adjacent cooperation cell, so that primary user and pairing user utilize same wireless resource to send information simultaneously; Base station, two cooperation cell receives respectively after the analog network coding information sending from two users, by cooperation, obtain the analog network coding information that another base station receives, and the analog network coding information of the analog network coding information that cooperation is obtained and self reception is carried out joint-detection, obtain this community primary user's transmission information, and eliminate the interference from pairing user.

Referring to Fig. 2, introduce following five concrete operation steps of the inventive method:

Step 1, two cooperative base station determine that cell edge adopts the excited users pair set of analog network coding transmission, this activations is formed by being positioned at the primary user of serving BS and being positioned at pairing user cooperative base station, that match with this primary user user; Judge again in this excited users pair set whether have the user couple who needs scheduling, if existed, carry out subsequent step 2; Otherwise, finish this operating process.

This step 1 comprises following content of operation:

(11) first cell base station BS1, by measuring the Signal to Interference plus Noise Ratio SINR of user reference signal, judges that whether this community user UE1 is this Cell Edge User, if so, carries out subsequent step (12); Otherwise, finish this flow operations;

(12) second cell base station BS2 travel through to find whether have the pairing user who adopts same wireless resource transmission with primary user UE1 in its Cell Edge User, if existed, the user UE2 and the primary user UE1 that meet this condition are matched, the user who again this primary user and pairing user is formed is to putting excited users pair set under, to carry out analog network coding transmission; Otherwise, finishing this flow operations, primary user UE1 adopts traditional non-collaborative network coded system transmission information;

(13) if in excited users pair set, have a plurality of can carry out the candidate user of analog network coding transmission with primary user UE1 pairing time, second base station BS 2 selected a pairing user UE2 from these candidate user according to following formula, allow its analog network coding that cooperates with primary user UE1 pairing transmit, this selection criterion is: , wherein, Σ is the set that all schedulable candidate user form, ue _ifor i user in this set Σ, h ₁, h ₂be respectively the channel fading information of two cooperative base station BS1 of primary user UE1 arrival and BS2, be respectively candidate user ue _iarrive the channel fading information of base station BS 1 and BS2.

Step 2, dispatch the primary user UE1 of the excited users centering of employing analog network coding transmission and pairing user UE2 according to predetermined priority respectively each base station.For example, base station can be select target to the maximum with throughput, from the candidate user centering of a plurality of Adoption Network coding transmission, selects user to dispatching.

Step 3, these two user UE1 and UE2 adopt identical Radio Resource to its base station, affiliated subdistrict and base station, adjacent cooperation cell, to send information simultaneously.

Step 4, two cooperative base station receive respectively the analog network coding information of two user UE1 and UE2 transmission, also by cooperation, obtain respectively analog network coding information and other required information of detection that another base station receives.

This step 4 comprises following content of operation:

(41) two cooperative base station BS1 and BS2 receive respectively the analog network coding information sending separately from primary user UE1 and pairing user UE2: y ₁=h ₁₁s ₁+ h ₁₂s ₂+ n ₁, y ₂=h ₂₁s ₁+ h ₂₂s ₂+ n ₂, wherein, y ₁and y ₂be respectively the network code information that base station BS 1 and BS2 receive, s ₁and s ₂respectively the transmission information of user UE1 and UE2, h ₁₁and h ₂₁for the channel fading information of primary user UE1 to this cell base station BS1 and neighbor cell base station BS2, h ₁₂and h ₂₂for the channel fading information of pairing user UE2 to neighbor cell base station BS1 and this little base station area BS2, n ₁and n ₂it is the additive white Gaussian noise at base station BS 1 and BS2 place;

(42) two cooperative base station adopt the connected X2 interface of optical fiber to communicate by it and realize cooperation, thereby obtain analog network coding information and other required information of detection that the other side receives.

Step 5, the analog network coding information that each base station obtains cooperation and the analog network coding information self receiving are carried out joint-detection, obtain this community primary user's transmission information.

This step 5 comprises following content of operation:

(51) base station BS 1 obtains by cooperation the analog network coding information y that another base station BS 2 receives ₂, and primary user UE1 and the channel fading information h of user UE2 to the other side's base station BS 2 that match ₁₂and h ₂₂after, the analog network coding information y that this base station BS 1 receives self ₁analog network coding information y with cooperation acquisition ₂carry out joint-detection.

With the operation while of above-mentioned steps, another base station BS 2 also obtains by cooperation the analog network coding information y that the other side's base station BS 1 receives ₁, and two user UE1 and UE2 are to the channel fading information h of the other side's base station BS 1 ₁₁and h ₂₁after, the analog network coding information y that this base station BS 2 receives self ₂analog network coding information y with cooperation acquisition ₁carry out joint-detection.

(52) two base station BSs 1 and BS2 adopt respectively following ZF (Zero-forcing) formula to detect to obtain the transmission information of primary user UE1 and pairing user UE2:

${\left[\begin{array}{cc}{\stackrel{\⩓}{s}}_1& {\stackrel{\⩓}{s}}_2\end{array}\right]}^T=\arg \underset{S_{1-K},S_{2-M}\∈\mathrm{\Ω}}{\min }\left|{\left[\begin{array}{cc}{h}_{11}& h_{12}\\ h_{21}& h_{22}\end{array}\right]}^{-1}{\left[\begin{array}{cc}{y}_1& y_2\end{array}\right]}^T\begin{array}{c}-{\left[\begin{array}{cc}{s}_{1-k}& s_{2-m}\end{array}\right]}^T\end{array}\right|,$ In formula, with respectively that base station BS 1 or BS2 detect two user UE1 obtaining and the transmission information of UE2, Ω be user UE1 and UE2 employing modulation coding mode the likely set of constellation point, s _1-kand s _2-mbe respectively a constellation point in Ω.

In order to assess the performance gain of the inventive method, applicant has carried out repeatedly implementing test, to the inventive method embodiment and other presence of intercell interference processing methods are compared on cell transmission performance gain.

Referring to Fig. 3, introduce the inventive method embodiment and adopt the Cell Edge User throughput ratio of other presence of intercell interference processing methods compared with schematic diagram.The experimental data of embodiment is: two adjacent cooperation cell edge customer numbers are 2, wireless transmission channel is flat Rayleigh fading channel, and the inventive method embodiment is compared with keeping pouring in transmission method with adopting respectively inter-cell interference coordination method, many antenna interference removing method and tradition.In Fig. 3, be respectively the inventive method, many antenna interference removing method from top to bottom, adopt the tradition of desirable serial interference elimination with keeping pouring in transmission method, inter-cell interference coordination method and tradition with keeping pouring in five Cell Edge User throughput-signal to noise ratio curves that transmission method is corresponding.

Experimental result shows, in transmitting signal to noise ratio, from 0dB, increase to the process of 30dB, two trial curves of the Cell Edge User throughput of the inventive method and many antenna interference removing method are identical and overlap together, and it is better than other several methods from start to finish.And along with sending the increase of signal to noise ratio, the advantage of the inventive method is more obvious.This is because the inventive method can be eliminated two interference between Cell Edge User completely, and compares with many antenna interference removing method, and the inventive method need to not increase in base station extra antenna configuration.

The foregoing is only preferred embodiment of the present invention, in order to limit the present invention, within the spirit and principles in the present invention not all, any modification of making, be equal to replacement, improvement etc., within all should being included in the scope of protection of the invention.

Claims (4)

1. a method that adopts cooperation analog network coding technology to suppress presence of intercell interference, it is characterized in that: match to its Cell Edge User base station, two adjacent cooperation cell, so that primary user and pairing user utilize same wireless resource to send information to serving BS separately simultaneously; Base station, two cooperation cell receives respectively after the analog network coding information sending from two users, by cooperation, obtain the analog network coding information that another base station receives, and the analog network coding information of the analog network coding information that cooperation is obtained and self reception is carried out joint-detection, obtain this community primary user's transmission information, and eliminate the interference from pairing user; The method is not changing under the prerequisite of existing communication equipment, eliminate presence of intercell interference, because pairing user adopts and primary user's same wireless resource is transmitted, solve the deficiency of disturbance coordination method between conventional cell simultaneously, improved throughput and the spectrum efficiency of Cell Edge User; Described method comprises following operating procedure:

(1) two cooperative base station determines that cell edge adopts the excited users pair set of analog network coding transmission, described activation to user by be positioned at the primary user of serving BS and be positioned at cooperative base station, formed with the pairing user of this primary user's pairing; Judge again in this excited users pair set whether have the user couple who needs scheduling, if existed, carry out subsequent step (2); Otherwise, finish this operating process; This step comprises following content of operation:

(11) first cell base station BS1, by measuring the Signal to Interference plus Noise Ratio SINR of user reference signal, judges that whether this community primary user UE1 is this Cell Edge User, if so, carries out subsequent step (12); Otherwise, finish this flow operations;

(12) second cell base station BS2 travel through to find whether have the pairing user who adopts same wireless resource transmission with primary user UE1 in its Cell Edge User, if existed, the user UE2 and the primary user UE1 that meet this condition are matched, the user who again this primary user and pairing user is formed is to putting excited users pair set under, to carry out analog network coding transmission; Otherwise, finishing this flow operations, primary user UE1 adopts traditional non-collaborative network coded system transmission information;

(13) if in excited users pair set, have a plurality of can carry out the candidate user of analog network coding transmission with primary user UE1 pairing time, second base station BS 2 selected a pairing user UE2 from these candidate user according to following formula, allow its analog network coding that cooperates with primary user UE1 pairing transmit, this selection criterion is: , wherein, Σ is the set that all schedulable candidate user form, ue _ifor i user in this set Σ, h ₁, h ₂be respectively the channel fading information of two cooperative base station BS1 of primary user UE1 arrival and BS2, be respectively candidate user ue _iarrive the channel fading information of base station BS 1 and BS2;

(2) dispatch the primary user UE1 of the excited users centering of employing analog network coding transmission and pairing user UE2 according to predetermined priority respectively each base station;

(3) these two user UE1 and UE2 adopt identical Radio Resource to its base station, affiliated subdistrict and base station, adjacent cooperation cell, to send information simultaneously;

(4) two cooperative base station receive respectively the analog network coding information of these two user UE1 and UE2 transmission, also by cooperation, obtain respectively analog network coding information and the required information of detection that another base station receives;

(5) the analog network coding information that each base station obtains cooperation and the analog network coding information self receiving are carried out joint-detection, and the primary user who obtains this base station sends information; This step comprises following content of operation:

(51A) base station BS 1 obtains by cooperation the analog network coding information y that another base station BS 2 receives ₂, and primary user UE1 and the channel fading information h of user UE2 to base station BS 2 that match ₁₂and h ₂₂after, the analog network coding information y that base station BS 1 receives self ₁analog network coding information y with cooperation acquisition ₂carry out joint-detection;

(51B) base station BS 2 obtains by cooperation the analog network coding information y that base station BS 1 receives ₁, and primary user UE1 and the channel fading information h of user UE2 to base station BS 1 that match ₁₁and h ₂₁after, the analog network coding information y that base station BS 2 receives self ₂analog network coding information y with cooperation acquisition ₁carry out joint-detection; The operation of this step (51B) is carried out with (51A) simultaneously;

(52) two base station BSs 1 and BS2 adopt respectively following ZF formula to detect to obtain primary user and pairing user's transmission information: ${\left[\begin{array}{cc}{\stackrel{\⩓}{s}}_1& {\stackrel{\⩓}{s}}_2\end{array}\right]}^T=\arg \underset{S_{1-K},S_{2-M}\∈\mathrm{\Ω}}{\min }\left|{\left[\begin{array}{cc}{h}_{11}& h_{12}\\ h_{21}& h_{22}\end{array}\right]}^{-1}{\left[\begin{array}{cc}{y}_1& y_2\end{array}\right]}^T\begin{array}{c}-{\left[\begin{array}{cc}{s}_{1-k}& s_{2-m}\end{array}\right]}^T\end{array}\right|,$ In formula, with respectively that base station BS 1 or BS2 detect two user UE1 obtaining and the transmission information of UE2, Ω be user UE1 and UE2 employing modulation coding mode the likely set of constellation point, s _1-kand s _2-mbe respectively a constellation point in Ω.

2. method according to claim 1, it is characterized in that: described two cooperative base station are by optical fiber, to connect the base station of the neighbor cell that its X2 interface cooperates or the base station and via node or base station and its spaced antenna that adopt optical fiber or back haul link to be connected.

3. method according to claim 1, is characterized in that: in described step (2), base station is to be select target to the maximum with throughput, from the candidate user centering of a plurality of employing analog network coding transmission, selects user to dispatching.

4. method according to claim 1, is characterized in that: described step (4) comprises following content of operation:

(41) two cooperative base station BS1 and BS2 receive respectively the analog network coding information sending from primary user UE1 and pairing user UE2: y ₁=h ₁₁s ₁+ h ₁₂s ₂+ n ₁, y ₂=h ₂₁s ₁+ h ₂₂s ₂+ n ₂, wherein, y ₁and y ₂be respectively the analog network coding information that base station BS 1 and BS2 receive, s ₁and s ₂respectively the transmission information of user UE1 and UE2, h ₁₁and h ₂₁for the channel fading information of primary user UE1 to this cell base station BS1 and neighbor cell base station BS2, h ₁₂and h ₂₂for the channel fading information of pairing user UE2 to neighbor cell base station BS1 and this little base station area BS2, n ₁and n ₂it is the additive white Gaussian noise at base station BS 1 and BS2 place;

(42) two cooperative base station adopt the connected X2 interface of optical fiber to communicate by it and realize cooperation, thereby obtain network code information and other required information of detection that the other side receives.